Final answer:
To enter "2020 Sales" as the bar chart title, click on the chart title placeholder, type in the text, and press Enter or click outside the text box to save it.
Step-by-step explanation:
To enter the text "2020 Sales" into the bar chart title placeholder, you first need to click on the placeholder that is labeled as 'Chart Title' or sometimes just represented by a box at the top of the bar chart. Once the text box is active (indicated by a blinking cursor), you can type in "2020 Sales." If the text does not automatically save, press the Enter key on your keyboard or click anywhere outside the text box to ensure the new title is set. This will update your chart to reflect the new title.